Custom window size and compression settings are not saved (reset to default with each new compress)
When you resize a window and close the app - it starts with the "default" size. In v3.8 you could at least define the UI scale to compensate that.
Same goes for compression settings. I have to select the desired algo, and tick the checkboxes for each and every one of the new root folders (if I'm compressing one folder, closing the app, then compressing an another folder through the context menu). Yes, you can "apply to all" if you're doing a batch, but, playing a guessing game as to whether I selected the right algo or not before I started the compression process on a beefy folder - is ... not fun at all. Again, v3.8 saved those settings, so when you opened up the app again - the desired algo was already selected (and "secondary" options were saved in the app's settings, ofc).
With all due respect, I genuinely don't get it why you had to reinvent the wheel, and made the vehicle lose control as the result. Yes, there's an old saying "If it works - don't fix it." - but there's even an older one stating "Done is better than perfect.". =)
It's still in beta for a reason :)